This paper proposes a method of designing fixed parameter decentralized power system stabilizers (PSS) for interconnected multi-machine power systems. Conventional design technique using a single machine infinite bus approximation involves the frequency response estimation called the GEP(s) between the AVR input and the resultant electrical torque. This requires the knowledge of equivalent external reactance and infinite bus voltage or their estimated values at each machine. Other design techniques using P-Vr characteristics or residues are based on complete system information. In the proposed method, information available at the high voltage bus of the step-up transformer is used to set up a modified Heffron-Phillip's model. With this model it is possible to decide the structure of the PSS compensator and tune its parameters at each machine in the multi-machine environment, using only those signals that are available at the generating station. The efficacy of the proposed design technique has been evaluated on three of the most widely used test systems. The simulation results have shown that the performance of the proposed stabilizer is comparable to that which could be obtained by conventional design but without the need for the estimation and computation of external system parameters.

Power System Stabilizers Design for Interconnected Power Systems

In this paper a new nonlinear excitation controller design to enhance transient stability of multimachine power systems is presented Partial feedback linearization is first used to transform the nonlinear power system model into a partially linear system comprising a reduced-order linear part and a nonlinear dynamic autonomous part Then a linear state feedback stabilizing controller is designed for the reduced-order linear part using optimal control theory to enhance the stability of the whole system In this way, the performance of the stabilizing controller would be independent of the operating points of the power system and therefore is superior to those designed for completely linearized systems It is shown that the controller design method ensures the stability of the nonlinear dynamic autonomous part The design method is applicable to multimachine power systems but tested on a 3-machine 11-bus two-area test system The performance of the proposed control scheme to large disturbances is evaluated, through computer simulation, and compared with a conventional power system stabilizer and an exact feedback linearizing controller

Partial Feedback Linearizing Excitation Controller for Multimachine Power Systems to Improve Transient Stability

In this paper, a technique for designing fixed parameter decentralized power system stabilizers (PSSs) for interconnected power systems is proposed. In the proposed method, local information available at each machine in the multimachine environment, is used to tune parameters of PSS. Conventional design techniques such as P-Vr frequency response approaches, and the method of residues are based on complete system information, wherein phase angles of residues are consistent with the P-Vr phase response and can be used with confidence for design purposes. It is shown that magnitude and phase information of the proposed GEP TF agrees closely with that of P-Vr TF and yields a robust stabilizer. Nonlinear simulation and eigenvalue analysis show the efficacy of the proposed stabilizer to damp out the interarea and local modes of oscillations effectively over a wide range of operating conditions. Superiority of the proposed approach over the conventional approaches is demonstrated with simulation studies on two widely used multimachine systems.

Power System Stabilizers Design for Multimachine Power Systems Using Local Measurements

Design of a nonlinear power system stabilizer using synergetic control theory

Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp the low frequency power system oscillations. To overcome the drawbacks of conventional PSS (CPSS), numerous techniques have been proposed in the literature. Based on the analysis of existing techniques, a novel design of power system stabilizer (PSS) based on heuristic dynamic programming (HDP) is proposed in this paper. HDP combining the concepts of dynamic programming and reinforcement learning is used in the design of a nonlinear optimal power system stabilizer. The proposed HDP based PSS is evaluated against the conventional power system stabilizer and indirect adaptive neurocontrol based PSS under small and large disturbances in a single machine infinite bus power system setup. Results are presented to show the effectiveness of this new technique.

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A heuristic dynamic programming based power system stabilizer for a turbogenerator in a single machine power system

This paper presents a practical design for a power system stabilizer using the differential geometric linearization approach. This stabilizer uses the information at the secondary bus of the step-up transformer as input signals, enabling its application to multi-machine power systems. The stabilizer makes it possible to obtain all necessary information within its own power station without observing an equivalent reactance in other power systems. To evaluate the dynamic performance of this stabilizer, the authors tested it on a multimachine power system computer model. The simulation results showed that the stabilizer offered good dynamic performance and robustness compared with conventional power system stabilizers, thus confirming its very effective and practical application in power system stabilization.

M. Nambu

Papers

Development of an advanced power system stabilizer using a strict linearization approach